[CFT][PATCH] cciss/cpqarray fixes (2.5)

	Folks, if you have access to cciss and/or cpqarray test boxen,
please check if ftp.linux.org.uk/pub/people/viro/T24-cciss-C68 and
ftp.linux.org.uk/pub/people/viro/T25-cpqarray-C68 restore the "allow
root to open device with minor 0 even if nothing had been configured"
behaviour.

	Changes:
a) we _always_ register gendisk for disk #0 on controller.
b) it stays registered until we forget about controller.
c) when old code would remove it, we merely set size to 0.

	That (presumably) fixes the breakage introduced in 2.5 when we
started to require registered gendisk for open(2).  Please, check if that
helps and doesn't introduce new breakage - I don't have either hardware, so
it's completely untested.  It builds, but that's it.